1. Field of the Invention
The invention relates machinery for automatically separating large quantities of unconsolidated material (i.e., construction or demolition debris, mined material, soils, recyclable material and the like). More particularly, the invention relates to a mobile trommel having multiple screening steps for easier and more refined separation of various grades of the unconsolidated material into at least three separate grades.
2. Description of the Background Art
Various industries require machinery that can mechanically separate unconsolidated material into different grades of consolidated material. For example, the demolition of a structure (i.e., masonry or block construction, or the like) produces a large quantity of rubble. Such rubble may sometimes have to be separated by size for use in backfilling or for proper carting and processing at a remote location. In mining operations it is necessary to process large amounts of material extracted from a mine and separate the ore from soil, rock and other non-valuable material. In the landscaping and gardening industries, it is necessary to produce various grades of fill material to suit specific purposes. Compost, mulch and finer grades of topsoil must be separated from bulk quantities of collected biodegradable refuse. Such materials are then distributed throughout a particular landscaping project dependent upon specific need.
In each instance and industry discussed above, large quantities of differently sized materials need to be separated. Performing such separation task by hand is slow, tedious and usually unprofitable for an operator of a business operating within such industry. Therefore, mechanical separators were developed to solve this problem.
Typically, one drum receives material to be separated, and the drum, which is provided with perforations or other such openings, is rotated to cause a mixing action of the material. The perforations in conjunction with the rotating action allow some material (smaller than the openings) to pass radially out of the drum for collection and further processing. Material that does not meet the size criteria is moved by gravity to the lower end of the drum and is carried away as waste. Unfortunately, only two grades of materials can be separated from such a single drum device (waste and processed material).
Therefore, a need exists in the art for a mechanical separator or trommel that is capable of separating raw material into more than two grades of materials.
A transportable trommel for separating mixtures of soils, debris, recyclable material or the like into three grades according to particle or grain size. The trommel is double skinned and has an inner drum with apertures of a first predetermined size and an outer drum with screens having openings in their mesh of a second predetermined size.